Random thoughts, musings, and tech stuff

18 Feb 2019, 20:50

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I recently started getting into watches. I guess that I’ve been interested in them for a long time, but the difference I guess is that I’ve started focusing on mechanical watches. Something that wormed its way into my brain was the thought of buying a bunch of parts and assembling a watch from scratch.

A couple months ago, I looked around at watch parts, and really had no idea what I was looking at and gave up quickly. Mainly, I didn’t really understand how to find a movement, and then match a dial, case, and hands to it. Then, I saw a post on Massdrop that had a couple shops to go to for parts, as well as a chronograph movement (Valjoux ETA 7750). I checked out Ofrei, and they had everything that I would need with a base Valjoux 7750 movement.

Total - ~$589 - not too bad, around the same price as the cheapest automatic chronograph I could find. However, the cheapest chronograph with a Valjoux 7750 movement was over $1000 (most were between $1500-4000), so I figure I’m a ahead here.

I had some of the required tools, but did need a few others, like a hand press, and some other odds and ends.

I had done a fair amount of research on all the different parts of assembling a watch from parts, and felt that overall I had a pretty good handle on everything. Once I actually started trying to place the chrono hands on the movement, my theory quickly fell apart, and I turned to r/WatchHorology for help. There were a few suggestions that were useful, but this one, by u/hal0eight I thought was the most helpful:

The trick here is the hands haven’t been fitted before, so they are quite tight. When you put it on the shaft it will want to move around rather than slightly go on.

You’ll need to line it up best you can on the shaft, then put the flat hand press end on top of the hand, move it around so you are applying a little pressure down, but also moving the hand around so it’s reasonably straight on the tip of the shaft.

When you’ve got it, gently push down.

If you need to reseat the hand it should be much easier.

As you can see, I used the Rodico sticky putty to hold the hand onto the hand press, and then was able to simply move the movement into place underneath it. That was a lot easier than trying to place the thing on there with tweezers.

After figuring that out, I was able to move on to place the other small chrono hand and the sub-second hand without issue.

Placing the larger hands was much easier, so they went on quickly. At this point, I started playing around with winding the movement to see if the thing worked, and was a bit concerned to find that the sub-second hand was not turning, and nothing on the movement seemed to be moving. I was able to manipulate it a bit to move for a few seconds at a time, but not much beyond that. I’m not sure, but I have a feeling that it was because I had removed the rotor. I think that without the rotor, something is allowed to spin freely that should have resistance on it. Something for me to read up on anyways.

I put the movement in the case, and figured out how to cut down the stem to size. This was particularly tricky with a screw-down crown. I ended up making several cuts, and now I think it’s perfect.

After that, I put the rotor back on the movement, put the case together, and did verify that the watch works correctly, and is able to keep time. The only thing that does not work right now is the minute chrono hand. I’m thinking there may be some residual Rodico in there, so when I’m feeling up to it, I’ll take the thing apart, and try to find out. If it’s not that, then I’ll be doing a much deeper dive on the Valjoux 7750 to try to diagnose it (asking reddit for help).